Problem with extrude along the local axis hotkeys
If you press a key for an axis like Z multiple times after activating a transformation like Scale (S), it will cycle through a few Transformation Orientations (Local, Normal, Global, ...).
You may have set a different value in the &quot;Transformation Orientations&quot; selection box than in the tutorial. Check the value of this box.
The selection box is located in the top center of the header of the viewport (or at the bottom of the viewport if the header is there). See screenshot here in Blender's documentation.